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Lithium metal batteries (LMBs) are considered the ideal choice for high volumetric energy density lithium‐ion batteries, but uncontrolled lithium deposition poses a significant challenge to the stability of such devices. In this paper, we introduce a 2.5 μm‐thick asymmetric and ultrastrong separator, which can induce tissue‐like lithium deposits. The asymmetric separator, denoted by utPE@Cu2O, was prepared by selective synthesis of Cu2O nanoparticles on one of the outer surfaces of a nanofibrous (diameter ~10 nm) ultrastrong ultrahigh molecular weight polyethylene (UHMWPE) membrane. Microscopic analysis shows that the lithium deposits have tissue‐like morphology, resulting in the symmetric lithium cells assembled using utPE@Cu2O with symmetric Cu2O coating exhibiting stable performance for over 2000 h of cycling. This work demonstrates the feasibility of a facile approach ultrathin separators for the deployment of lithium metal batteries, providing a pathway towards enhanced battery performance and safety. [ABSTRACT FROM AUTHOR]

Aseptic loosening of orthopedic implants is an inflammatory disease characterized by immune cell activation, chronic inflammation, and destruction of periprosthetic bone, and is one of the leading reasons for prosthetic failure, affecting 12% of total joint arthroplasty patients. Matrix-bound nanovesicles (MBVs) are a subclass of extracellular vesicle recently shown to mitigate inflammation in preclinical models of rheumatoid arthritis and influenza-mediated "cytokine storm." The molecular mechanism of these anti-inflammatory properties is only partially understood. The objective of the present study was to investigate the effects of MBV on RANKL-induced osteoclast formation in vitro and particulate-induced osteolysis in vivo. Results showed that MBV attenuated osteoclast differentiation and activity by suppressing the NF-κB signaling pathway and downstream NFATc1, DC-STAMP, c-Src, and cathepsin K expression. In vivo, local administration of MBV attenuated ultrahigh molecular weight polyethylene particle-induced osteolysis, bone reconstruction, and periosteal inflammation. The results suggest that MBV may be a therapeutic option for preventing periprosthetic loosening. [ABSTRACT FROM AUTHOR]

Ultrahigh molecular weight polyethylene (UHMWPE) fibers possess excellent mechanical properties, yet their applications are severely limited by surface inertness and low melting points. To enhance surface activity and temperature resistance, soluble polyimide (PI) is applied to the surface of UHMWPE fibers. A mussel‐inspired biomimetic polycatechol/polyamine (PA) coating is initially constructed on the UHMWPE fiber surface by oxidative self‐polymerization, serving as a secondary reaction platform. Subsequently, multifunctional UHMWPE‐PA‐PI fibers are prepared by depositing soluble PI on the fiber surface via impregnation. The PA and PI layers are firmly bonded by hydrogen bonding interactions and physical adhesion. The results show that the PI‐coated UHMWPE fiber surface exhibits enhanced chemical activity, hydrophilicity, and thermal stability, with an increased thermal decomposition temperature of approximately 30 °C. Compared to pristine UHMWPE, the breaking force of UHMWPE‐PA‐PI fibers increases by 14.9%, and the interfacial adhesion strength between the fiber and rubber improves by 65.5%. The PI coatings also provide thermal insulation, acid resistance, and erasability functionalities. This modification strategy is highly efficient, simple, and less damaging, offering a novel solution to address UHMWPE fibers' surface inertness and temperature intolerance. [ABSTRACT FROM AUTHOR]

SCI America's annual Innovation Day brought together early-career scientists to discuss scientific advancements and challenges in the chemical industry. The event featured panel sessions on leadership and regulation, and recognized Caleb Funk and Max McDaniel for their contributions to water purification membranes and catalyst technologies, respectively. SCI is also hosting the Bright SCIdea competition for university students to develop entrepreneurial ideas with societal benefits. Greg Clark has been appointed as the Chair of the Board of Trustees at SCI. The text also announces the SCI Innovation Award and the SCI Leadership in Diversity in Science-Led Industry Award, both of which are currently accepting nominations until November 30, 2024. [Extracted from the article]

The surface properties and chemical structure of nanosized coatings deposited on the surface of polyethylene terephthalate track-etched membranes by magnetron sputtering of ultrahigh molecular weight polyethylene and polytetrafluoroethylene in a vacuum have been studied. Application of coatings leads to hydrophobization of surface of the original membranes, the degree of which depends on the type of polymer used for sputtering and the coating thickness. The use of this modification method causes smoothing of structural inhomogeneities of the surface layer of membranes, which is explained by the deposition of coatings in the pore channels at a certain depth from the inlet and the overlap of pores on the surface of modified membranes. In addition, the deposition of coatings on the surface of track-etched membranes leads to a change in the shape of pores. The pore diameter decreases significantly on the modified side and remains unchanged on the untreated side of the membrane, while the membrane pores acquire an asymmetrical (conical) shape. The study of chemical structure of coatings using X-ray photoelectron spectroscopy showed that they contain oxygen-containing functional groups owing to oxidation of the polymer matrix. The developed composite membranes can be used in membrane distillation processes for seawater desalination. [ABSTRACT FROM AUTHOR]

In this work, four kinds of silica with similar textural properties but different particle size (PS) from 6 to 60 μm were selected as support to prepare silyl‐chromate/VOx/silica bimetallic catalysts for ethylene polymerization, thus making it possible to conduct convincing investigation on the effects of catalyst PS over catalytic behaviors and polymer properties. It is found, owing to mass‐ and heat‐transfer limitations, the catalysts with smaller PS showed higher initial activity, while the deactivation in the later stage was more remarkable. Meanwhile, catalysts with smaller PS synthesized bimodal ultrahigh molecular weight polyethylene/high‐density polyethylene in‐reactor blends (UHMWPE/HDPE IRBs) with higher molecular weight (MW) and narrower molecular weight distribution (MWD). Four PE sample couples with MW increasing from 5 × 105 to 10 × 105 g mol−1 and PS from 40 to 460 μm were selected for tensile and rheological tests. For each couple with similar MW and MWD, the sample with smaller PS always had larger tensile strength and breaking elongation. The cryogenically fractured surface of the samples made by smaller PE particles showed fewer delamination defects and unfused small particles. The rheological results indicate that higher homogeneity was achieved for the sample with smaller PS, which was reflected by the unexpected higher viscosity and storage modulus. [ABSTRACT FROM AUTHOR]

Total ankle arthroplasty (TAA) is a motion-preserving treatment for end-stage ankle arthritis. An effective tool for analyzing these implants' mechanical performance and longevity in silico is finite element analysis (FEA). An FEA in ABAQUS was used to statically analyze the mechanical behavior of the ultra-high-molecular-weight polyethylene (UHMWPE) bearing component at varying dorsiflexion/plantarflexion ankle angles and axial loading conditions during the stance phase of the gait cycle for a single cycle. The von Mises stress and contact pressure were examined on the articulating surface of the bearing component in two newly installed fixed-bearing TAA implants (Wright Medical INBONE II and Exactech Vantage). Six different FEA models of variable ankle compressive load levels and ankle angle positions, for the varying subphases of the stance phase of the gait cycle, were created. The components in these models were constrained to be conducive to the bone–implant interface, where implant loosening occurs. Our results showed that the von Mises stress and contact pressure distributions increased as the compressive load increased. The highest stress was noted at dorsiflexion angles > 15°, in areas where the UHMWPE liner was thinnest, at the edges of the talar and UHMWPE components, and during the terminal stance phase of the gait cycle. This static structural analysis highlighted these failure regions are susceptible to yielding and wear and indicated stress magnitudes that are in agreement (within 25%) with those in previous static structural TAA FEAs. The mechanical wear of the UHMWPE bearing component in TAA can lead to aseptic loosening and peri-implant cyst formation over time, requiring surgical revision. This study provides ankle replacement manufacturers and orthopedic surgeons with a better understanding of the stress response and contact pressure sustained by TAA implants, which is critical to optimizing implant longevity and improving patient care. [ABSTRACT FROM AUTHOR]

Ultrahigh molecular weight polyethylene (UHMWPE) is suitable for tribological applications in various environments because of its advantageous characteristics, including its high‐impact strength, excellent resistance against wear and corrosion, and self‐lubricating properties. However, the tribological behavior of UHMWPE under seawater lubrication is still poorly understood. In this study, the wear mechanisms of UHMWPE in seawater environment were elucidated by examining its morphology and structural evolution during sliding friction. The tribological properties of UHMWPE were significantly affected by the sliding speed in seawater. At low sliding speeds, no long‐strip structures were observed on the worn UHMWPE surface. However, as the sliding speed was increased, prominent convex long‐strip structures appeared and became more densely distributed with time. The molecular chains in the amorphous region of UHMWPE stretched along the sliding direction under stress. In the crystalline region, molecular orientation, and lamellar slip were accompanied by molecular conformational transformations. During the initial stage of sliding friction, UHMWPE mainly exhibited adhesive wear caused by plastic deformation. Subsequently, the wear mechanism of UHMWPE gradually changed from adhesive wear to a combination of adhesive and abrasive wear, and its wear intensified over time. [ABSTRACT FROM AUTHOR]

The addition of two-dimensional inorganic nanomaterials can effectively enhance the properties of polyethylene (PE). In the present study, a series of high-performance PE/oleic acid (OA)–siloxene nanocomposites were prepared by in situ polymerization using OA–siloxene-supported Ziegler–Natta catalysts. Compared with the conventional Ziegler–Natta catalyst, the polymerization activity of the OA–siloxene-supported Ziegler–Natta catalyst was enhanced to 100 kg/mol-Ti•h, an increase of 56%. The OA–siloxene fillers exhibited excellent dispersion within the PE matrix through the in situ polymerization technique. Compared to pure PE, PE/OA–siloxene nanocomposites containing 1.13 wt% content of OA–siloxene showed 68.3 °C, 126%, 37%, and 46% enhancements in Tdmax, breaking strength, modulus, and elongation at break, respectively. [ABSTRACT FROM AUTHOR]

As the risk of social security increases, it is crucial to develop flexible protective materials that combine flexibility with high protective performance. Ultra-high-molecular-weight polyethylene (UHMWPE) was selected as the raw material, and four types of flat-knitting cut-resistant fabrics were ultimately designed and prepared from a three-dimensional longitudinal dimension and concave–convex array structure based on rib knitting. A series of experiments must be conducted on fabrics in order to study the law of protection performance of different structural fabrics. They were thus subjected to comprehensive evaluation and theoretical analysis of cut resistance. The results demonstrate that the four structural fabrics exhibited resilience in abrasion tests, withstanding over 100,000 cycles without failure. A weighting algorithm was employed to determine the comprehensive cutting resistance of the S1, S2, S3, and S4 structural fabrics, resulting in values of 1939.9 gf, 2298.6 gf, 2577.1 gf, and 2822.2 gf, respectively. Therefore, S1 reached class A4, which is sufficient to address a medium cut hazard. Similarly, S2, S3, and S4 reached class A5, which is adequate to address a high cut hazard. The obtained fitting equation, with uniform yarn fineness T as the dependent variable, demonstrates that the cut resistance improved as the concave–convex density level increased. [ABSTRACT FROM AUTHOR]

Polymer matrix types of fiber hybrid composites are key factors to improve ballistic impact damage tolerances. Here we report ballistic penetration damages of Kevlar/ultra-high molecular weight polyethylene (UHMWPE) hybrid composites with thermoplastic polyurethane (PU) matrix. The hybrid composites were penetrated by fragment-simulating projectiles (FSPs) using an air gun impact system. The effects of stacking sequences on the ballistic performance of hybrid composites were analyzed. Two types of specific energy absorption (the energy absorption per unit area density and the energy absorption per unit thickness) were investigated. It was found that the main damage modes of PU hybrid composites were fiber breakage, matrix damage, fiber pullout and interlayer delamination. The instantaneous deformation could not be used as a reference index for evaluating the ballistic performance of the target plate. The energy absorption process of the PU hybrid composites showed a nonlinear pattern. The hybrid structure affected the specific energy absorption of the materials. [ABSTRACT FROM AUTHOR]

Simple Summary: Rupture of the cranial cruciate ligament (CrCL) is a common condition in dogs, causing instability of the stifle, pain, lameness, osteoarthritis, and meniscal tears. Common treatments consist of tibial osteotomies or extra-articular stabilization of the stifle according to the size and weight of the dog. The most marginal routine practice is intra-articular stabilization, which consists of replacing the ruptured CrCL with an organic graft or a synthetic implant. This case report describes the technique used for the intra-articular synthetic reconstruction of the CrCL under arthroscopic guidance in a dog. This report is supported by a six-month clinical outcome assessment consisting of orthopedic examinations and radiographs. The dog showed quick resumption to normal gait and standing posture with no worsening of osteoarthritis and synovial effusion or complications. Mild signs of stifle instability were observed with no impact on clinical outcome. This technique could be considered an alternative for the treatment of CrCL rupture in dogs, but it needs confirmation from additional clinical studies with more dogs. The intra-articular reconstruction of the cranial cruciate ligament (CrCL) by an organic graft or a synthetic implant allows the restoration of physiological stifle stability. This treatment is still marginal in routine practice. A Rottweiler presented an acute complete CrCL rupture treated using an ultra-high-molecular-weight polyethylene (UHMWPE) implant. The latter was positioned under arthroscopic guidance and fixed with interference screws through femoral and tibial bone tunnels. The dog was weight-bearing just after surgery and resumed normal standing posture and gait after one month, with mild signs of pain upon stifle manipulation. At three months postoperatively, minimal muscle atrophy and minimal craniocaudal translation were noted on the operated hindlimb, with no effects on the clinical outcome. The stifle was painless. At six months postoperatively, standing posture and gait were normal, muscle atrophy had decreased, the stifle was painless, and the craniocaudal translation was stable. On radiographs, congruent articular surfaces were observed without worsening of osteoarthrosis over the follow-up, as well as stable moderate joint effusion. Replacement of a ruptured CrCL with a UHMWPE ligament yielded good functional clinical outcome at six months postoperatively. This technique could be considered an alternative for the treatment of CrCL rupture in large dogs, but it needs confirmation from a prospective study with more dogs. [ABSTRACT FROM AUTHOR]

Soft pouch motors, engineered to mimic the natural movements of skeletal muscles, play a crucial role in advancing robotics and exoskeleton development. However, the fabrication techniques often involve multistage processes; they lack soft sensing capabilities and are sensitive to cutting and damage. This work introduces a new textile‐based pouch motors with the capacity for biaxial actuation and capacitive sensory functions, achieved through the application of computerized knitting technology using ultrahigh molecular weight polyethylene yarn (Spectra) and conductive silver yarns. This method enables the rapid and scalable mass fabrication of robust pouch motors. The resulting pouch motors exhibit maximum lifting capacity of 10 kg, maximum contraction of 53.3% along the y‐axis, and transverse extension of 41.18% along the x‐axis at 50 kPa pressure. Finite element analysis closely matches the experimental data. The capacitance signals in relation to contraction motion are well suited for detecting air pressure levels and hold promise for applications requiring robotic control. Notably, it effectively elevates an ankle joint simulator at a 20° angle, highlighting its potential for applications such assisting individuals with foot drop. This study presents a practical demonstration of the soft ankle exosuit designed to provide lifting support for individuals facing this mobility challenge. [ABSTRACT FROM AUTHOR]

With the rapid development of the pipeline transportation and exploitation of mineral resources, there is an urgent requirement for high-performance polymer matrix composites with low friction and wear, especially under oxidative and prolonged working conditions. In this work, ultra-high-molecular-weight polyethylene (UHMWPE) matrix composites with the addition of carbon fibers (CFs), TiC, and MoS2 were prepared by the hot press sintering method. The influence of thermal oxygen aging time (90 °C, 0 h–64 h) on their mechanical and frictional performance was investigated. The results showed that TiC ceramic particles can increase wear resistance, especially by aging times up to 32 and 64 h. The wear mechanisms were analyzed based on the results of SEM images, EDS, and Raman spectra. The knowledge obtained herein will facilitate the design of long-service-life polymer matrix composites with promising low friction and wear performances. [ABSTRACT FROM AUTHOR]

As advances in heat resistant ultrahigh molecular weight polyethylene (UHMWPE) fiber via ultraviolet (UV) crosslinking, it is worth paying attention to its thermal aging behavior and heat resistance mechanism. UHMWPE fibers in different forms, the fully drawn yarn (FDY) and the UV crosslinked FDY (UVFDY), are subjected to isothermal aging at 135°C. The effects of thermal aging on their surface morphology and mechanical properties are studied and compared initially. The results demonstrate that UVFDY is a kind of a heat‐resistant fiber. Subsequently, to reveal the heat resistance mechanism of UVFDY, its crystalline and orientation structure evolution during thermal aging are further studied. It is indicated that the formation of dense‐packing crystals and disorientation behavior lead to fiber shrink, so that a number of grooves appear on the fiber surface. Since the crosslinked stucture of UVFDY hinders its molecules movement, the crystallization and disorientation behavior of UVFDY are weaker than those of FDY, resulting in UVFDY possesses slighter thermal shrinkage (Ts), fewer grooves and better mechanical properties than those of FDY. Therefore, the heat resistance of the fiber improves effectively after UV crosslinking. This work provides insights into the structure–property relationship of UVFDY during thermal aging, and offers basis data for its application in specific conditions. [ABSTRACT FROM AUTHOR]

Purpose: With the rapid development of the pipeline transportation and exploitation of mineral resources, it is urgent requirement for the high-performance polymer matrix composites with low friction and wear to meet the needs of solid material transportation. This paper aims to prepare high-performance ultrahigh molecular weight polyethylene (UHMWPE) matrix composites and investigate the effect of service condition on frictional behavior for composite. Design/methodology/approach: In this study, UHMWPE matrix composites with different content of MoS2 were prepared and the tribological performance of the GCr15/composites friction pair in various sliding speeds (0.025–0.125 m/s) under dry friction conditions were studied by ball-on-disk tribology experiments. Findings: Results show that the frictional behavior was shown to be sensitive to MoS2 concentration and sliding velocity. As the MoS2 content is 2 Wt.%, composites presented the best overall tribological performance. Besides, the friction coefficient fluctuates around 0.21 from 0.025 to 0.125 m/s sliding speed, while the wear rate increases gradually. Scanning electron microscopy images, energy-dispersive spectroscopy and Raman Spectrum analysis present that the main wear mechanisms were abrasive and fatigue wear. Originality/value: The knowledge obtained herein will facilitate the design of UHMWPE matrix composites with promising self-lubrication performances which used in slag transport engineering field. [ABSTRACT FROM AUTHOR]

The abalone shell, a composite material whose cross-section is composed of inorganic and organic layers, has high strength and toughness. Inspired by the abalone shell, several multi-layer composite plates with different layer sequences and thicknesses are studied as bullet-proof material in this paper. To investigate the ballistic performance of this multi-layer structure, the complete characterization model and related material parameters of large deformation, failure and fracture ofAl2O3 ceramics andCarbon Fiber Reinforced Polymer (CFRP) are studied. Then, 3D finite element models of the proposed composite plates with different layer sequences and thicknesses impacted by a 12.7 mm armor-piercing incendiary (API) are built using Abaqus to predict failure. The simulation results show that the CFRP/Al2O3 ceramic/Ultrahigh Molecular Weight Polyethylene (UHMWPE)/CFRP (1 mm/4 mm/4 mm/1 mm) composite is the optimized stack of layers. The simulation results under specified layer sequence and thickness have a reasonable correlation with the experimental results and reflect the failure and fracture of the multi-layer composite protective armor. [ABSTRACT FROM AUTHOR]

Previous studies have shown that gel‐spun‐ultra‐high‐molecular‐weight polyethylene (UHMWPE) produces thin fibril products that exhibit high tensile moduli (35–200 GPa). The elaborate gel‐spinning process involves complex drawing stages with solvent incorporation. In this study, a previously proposed two‐stage, environmentally friendly solventless methodology was optimized. The two‐stage process included cross‐rolling (Stage 1) and orientation (Stage 2) to obtain oriented HDPE thin rods with an impressively high modulus using conventional HDPE. The optimization of the process was successfully achieved by thoroughly investigating the voiding mechanism. In addition, rapid relaxation during orientation supports the cavitation mechanism. Owing to this optimization, a modulus of 75 GPa was readily attained. The significant enhancement in the mechanical properties was a direct result of the optimization of our processing methodology to achieve a high degree of orientation. Notably, the fabricated oriented HDPE thin rods showed moduli comparable to those of the gel‐spun UHMWPE fibers but were at least 40 times thicker. Our comprehensive characterization of the voiding process and stress relaxation during our two‐stage process indicated the formation of a highly taut network structure and craze‐like configuration with controlled delamination. Thus, our proposed hierarchical model was refined to elucidate the process‐structure‐property relationships in greater detail. Highlights: An optimized two‐stage environmentally friendly solventless process has been developed to create oriented polyethylene thin rods with impressively high modulus (75 GPa).The optimization was achieved by thoroughly investigating the voiding effect during cross‐rolling and crystalline relaxation during orientation.Comparison of the modulus from our process are similar to various commercial, gel‐spun fibers. Our thin rod products are at least 40 times thicker than commercial gel‐spun fibers.The thin rod product has impressively high modulus‐to‐weight and strength‐to‐weight ratios for future study in composite systems. [ABSTRACT FROM AUTHOR]

PURPOSE OF STUDY Total joint replacements (TJR) have become the cornerstone of modern orthopedic surgery. A great majority of TJR employs ultrahigh molecular weight polyethylene (UHMWPE) liners. TJR manufacturers use many different types of UHMWPE, which are modified by various combinations of crosslinking, thermal treatment, sterilization and/or addition of biocompatible stabilizers. The UHMWPE modifications are expected to improve the polymer’s resistance to oxidative degradation and wear (release of microparticles from the polymer surface). This manuscript provides an objective, non-commercial comparison of current UHMWPE formulations currently employed in total knee replacements. MATERIALS AND METHODS UHMWPE liners from 21 total knee replacements (TKR) were collected which represent the most implanted liners in the Czech Republic in the period 2020–2021. The UHMWPEs were characterized using several methods: infrared microspectroscopy (IR), non-instrumented and instrumented microindentation hardness testing (MH and MHI), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and solubility measurements. The above-listed methods yielded quite complete information about the structure and properties of each UHMWPE type, including its potential long-term oxidation resistance. RESULTS For each UHMWPE liner, IR yielded information about immediate oxidative degradation (in the form of oxidation index, OI), level of crosslinking (trans-vinylene index, VI) and crystallinity (CI). The MH and MHI testing gave information about the impact of structure changes on mechanical properties. The remaining methods (DSC, TGA, and solubility measurements) provided additional information regarding the structure changes and resistance to long-term oxidative degradation. Statistical evaluation showed significant differences among the samples as well as interesting correlations among the UHMWPE modifications, structural changes, and mechanical performance. DISCUSSION Surprisingly enough, UHMWPE materials from different manufacturers showed quite different properties, including the resistance against the long-term oxidative degradation, which is regarded as one of the main reasons of TJR failures. The most promising UHMWPE types were crosslinked materials with biocompatible stabilizers. CONCLUSIONS Current UHMWPE liners from different manufactures used in total knee replacements exhibit significantly different structure and properties. From the point of view of clinical practice, the traditional UHMWPE types, which contained residual radicals from irradiation and/or gamma sterilization, showed inferior resistance to oxidative degradation and should be avoided. The best properties were observed in modern UHMWPE types, which combined crosslinking, biocompatible stabilizers, and sterilization by ethylenoxide or gas plasma. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this cross‐sectional study was to compare survival, clinical and radiographic results of total knee arthroplasty (TKA) with vitamin E‐stabilized polyethylene (VEPE) or conventional polyethylene (CPE) at a minimum of 7‐year follow‐up. Methods: Patients who underwent primary TKA between 2011 and 2015, receiving the same cemented rotating platform knee design with VEPE or CPE tibial inserts, were identified. Patients were contacted for clinical and radiographic follow‐up. American Knee Society Score (KSS), Forgotten Joint Score (FJS‐12), presence of periprosthetic radiolucent lines (RLLs) and osteolysis were evaluated at the last follow‐up. Any revision, reintervention or other complications were recorded. Results: Among 350 TKAs initially identified, 102 VEPE and 97 CPE knees were included for analysis with mean follow‐up of 8.5 and 8.3 years, respectively. No significant difference was found in survival rates at 10‐year follow‐up with revision due to aseptic loosening (95.0% vs. 97.8%, p = 0.29) or due to any reason (87.6% vs. 89.6%, p = 0.78) between VEPE and CPE TKA. KSS function score resulted significantly higher in the VEPE group over CPE (77 vs. 63, p = 0.01). RLLs were more frequent in VEPE than CPE (54% vs. 32%, p = 0.05), mainly noticed medially and posteriorly beneath the tibial plate, adjacent to the trochlear shield and the posterior condyles. Osteolysis was observed in one knee per group, but patients were asymptomatic with stable implants. Conclusion: TKA with VEPE and CPE tibial inserts showed comparable survival rates, complications and clinical and radiographic results up to 10‐year follow‐up. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

A hybrid of halloysite nanotubes decorated with titanium dioxide nanoparticles (HNTs@TiO2) was synthesized by the sol–gel method and then mixed with ultra‐high molecular polyethylene (UHMWPE) by melt compounding to enhance its wear resistance properties. The incorporation of HNTs@TiO2 increased the crystallinity as well as the hardness of UHMWPE nanocomposites, which benefited less prone to plastic deformation during the friction process. In addition, the UHMWPE/HNTs@TiO2 maintained a high ductility character with a slight decrease in tensile strength compared to pure UHMWPE. With the addition of 3 wt% HNTs@TiO2, the UHMWPE nanocomposite achieved a remarkably low friction coefficient of 0.073 and a reduced wear rate of 6.67 × 10−6 mm3/N·m. These values represented a 32.4% decrease in friction coefficient and a 43.9% decrease in wear rate compared to pure UHMWPE. The improvement in wear resistance was due to the dislodged TiO2 and HNTs had good synergistic rolling effects at the counterface. Furthermore, the wear scan morphology observation revealed that the transferred HNTs@TiO2‐based materials could help to improve the quality of the tribofilms, which alleviated the abrasive wear from the metallic counterpart. This work offers a feasible way to enhance the wear resistance of UHMWPE nanocomposite without sacrificing the high ductility for expanding its engineering applications. Highlights: TiO2‐decorated halloysite nanotubes were synthesized by the sol–gel method.The addition of HNTs@TiO2 maintained the high ductility character of UHMWPE.The UHMWPE composite with 3 wt% HNTs@TiO2 had the best wear resistance. [ABSTRACT FROM AUTHOR]

The impact resistance of layered polymer structures using polyvinyl butyral (PVB) in combination with Kevlar® fabric and ultra-high molecular weight polyethylene (UHMWPE) were fabricated and tested. Methods of wet impregnation and hot-press impregnation and consolidation of fabric with PVB and UHMWPE were used to manufacture multilayer constructs. All sandwich constructs were fixed to the surface of ballistic clay and subject to a free drop-weight test with a conical impactor having a small contact area. All tests were made at the same impact energy of 9.3 J and velocity of 2.85 m/s. The change in the resistance force was recorded using a piezoelectric force sensor at the time intervals of 40 μs. Using experimental force–time history, the change in the impactor's velocity, the depth of impactor penetration, the energy transformation at various stages of impactor interaction with the sample, and other parameters were obtained. Three indicators were considered as the main criteria for the effectiveness of a sample's resistance to impact: (1) minimum deformation, bulging, of the panel backside at the moment of impact, (2) minimum absorption of impact energy per areal density, and (3) minimal or, better yet, no destruction of structural integrity. Under the tested conditions, the rigid Kevlar–PVB–Kevlar sandwich at the frontside and relatively soft but flexible UHMWPE–Kevlar–UHMWPE layers in the middle helped to localize and absorb impact energy, while the backside Kevlar–PVB–Kevlar sandwich minimized local bulging providing the best overall performance. The front layer damage area was very shallow and less than two impactor tip diameters. The backside bulging was also less than in any other tested configurations. [ABSTRACT FROM AUTHOR]

The challenging melt processing of ultrahigh‐molecular‐weight polyethylene (UHMWPE) melt spinning hinders its efficiency and quality, which can be improved by processing aids that enhance its flowability. Building upon modifications of UHMWPE with high‐density polyethylene (HDPE), this article studies the effects of CaSt2, polyethylene glycol (PEG), silicone powder, and their compound additives on the processing performance of UHMWPE/HDPE blends. The modification effects and mechanisms are studied by analyzing processing torque, melt flow rate, viscoelastic activation energy, and rheological performance. The research results indicate that 1 wt% PEG significantly improves the processing flowability of UHMWPE/HDPE blends, and PEG mainly plays an internal lubrication role on the molecular chains of the blends. The combination of 0.5 wt% CaSt2 and 0.5 wt% silicone powder exhibits a synergistic effect of internal and external lubrication on the UHMWPE/HDPE blends melt processing, further improving the processing performance of UHMWPE/HDPE blends. Compared with unmodified blends, the maximum screw speed for obtaining qualified as‐spun filaments of UHMWPE/HDPE blends modified with CaSt2/silicone powder compound additives increases from 5 to 20 rpm, which means that the critical shear rate of the modified UHMWPE/HDPE blend melt processing is significantly improved. Meanwhile, the processing torque decreases by about 22%. [ABSTRACT FROM AUTHOR]

The influence of the polymer fraction structure on the physico-mechanical properties of bimodal reactor polymer compositions based on ultrahigh molecular weight polyethylene has been studied. The compositions included 30 wt % of the modifying polymer fractions. They represent linear high-density polyethylene with a molecular weight of 160, 110, and 48 kg/mol and branched ethylene/hexene-1 copolymers with the hexene-1 content of 6.3 and 8 mol % introduced into compositions directly in the synthesis. The thermal properties of materials have been studied by means of the DSC method. The presence of linear low molecular weight polyethylene fractions of highly crystallinity (62–83%) in compositions with ultrahigh molecular weight polyethylene of low crystallinity (52.5%) leads to a sharp increase in the content of the crystalline phase in the materials. Compositions with branched copolymer fractions have the lower degree of crystallinity (28.4 and 23%). A correlation was found between the content of the crystalline phase and the values of the elastic modulus of reactor compositions. For compositions including linear low molecular weight polyethylene, there is a sharp increase in this indicator up to 1100–1535 MPa relative to unmodified ultrahigh molecular weight polyethylene (733 MPa) with approach to the values characteristic of pure polyethylene (1230–1670 MPa). Branched copolymer fractions cause a decrease in the modulus of elasticity to 151–345 MPa. All the studied compositions demonstrate sufficiently high strength properties. The values of elongation at break exceed this characteristic of unmodified ultrahigh molecular weight polyethylene (550±36%) and vary in the range from 560±14 to 850±22%. The introduction of modifying polymer fractions led to the appearance of fluidity of compositions based on ultrahigh molecular weight polyethylene. [ABSTRACT FROM AUTHOR]

Highly filled powder composites based on Al2O3 particles with a two-layer coating of ultra-high molecular weight polyethylene and low molecular weight polyethylene (Al2O3/UHMWPE/PE) were obtained by polymerization filling (in-situ) by successive two-stage polymerization, with a single-layer coating of ultra-high molecular weight polyethylene (Al2O3/UHMWPE) and low molecular weight polyethylene (Al2O3/PE) in a one-step process for 3D printing applications by selective laser sintering. Al2O3 corundum spheres with an average particle size of 20 μm were used as a filler, which provided the composite particles with a spherical shape and the necessary fluidity in the printer chamber. The melting temperature of nascent composites is higher than after melting, which widens the "sintering window," and is important for 3D printing by means of selective laser sintering. The dynamic loss modulus in the α-relaxation region, which characterizes the mobility of polymer chains in the intercrystalline (amorphous) layer, is higher for Al2O3/UHMWPE/PE composites than for Al2O3/UHMWPE, their plasticity under uniaxial tension has also increased. The heat resistance of the synthesized composites, estimated by the method of dynamic mechanical analysis, is 20–33°C higher than that of ultrahigh molecular weight polyethylene. The content of the filler, the arrangement of polymer layers on the surface of the filler particles, and their composition affect the strength properties and the nature of the deformation of composites under uniaxial tension. The resulting composites with a filling of 10 and 30 vol % showed high strength and deformation properties. Composite powders have been successfully tested in 3D printing by selective laser sintering, warping and shrinkage of parts were not observed. [ABSTRACT FROM AUTHOR]

Ultra-high-molecular-weight polyethylene (UHMWPE) components for orthopedic implants have historically been integrated into metal backings by direct-compression molding (DCM). However, metal backings are costly, stiffer than cortical bone, and may be associated with medical imaging distortion and metal release. Hybrid-manufactured DCM UHMWPE overmolded additively manufactured polyetheretherketone (PEEK) structural components could offer an alternative solution, but are yet to be explored. In this study, five different porous topologies (grid, triangular, honeycomb, octahedral, and gyroid) and three surface feature sizes (low, medium, and high) were implemented into the top surface of digital cylindrical specimens prior to being 3D printed in PEEK and then overmolded with UHMWPE. Separation forces were recorded as 1.97–3.86 kN, therefore matching and bettering the historical industry values (2–3 kN) recorded for DCM UHMWPE metal components. Infill topology affected failure mechanism (Type 1 or 2) and obtained separation forces, with shapes having greater sidewall numbers (honeycomb-60%) and interconnectivity (gyroid-30%) through their builds, tolerating higher transmitted forces. Surface feature size also had an impact on applied load, whereby those with low infill-%s generally recorded lower levels of performance vs. medium and high infill strategies. These preliminary findings suggest that hybrid-manufactured structural composites could replace metal backings and produce orthopedic implants with high-performing polymer–polymer interfaces. [ABSTRACT FROM AUTHOR]

In this study, the ballistic resistance of SiC (silicon carbide) and a SiC mixture S80B20 (80% SiC/20% B4C) backed with UHMWPE (ultra-high-molecular-weight-polyethylene) fiber board was investigated by striking it with a.30-06 armor piercing projectile. The front plate of the high hardness ceramics is intended to passivate the bullet and limit the bullet's impact kinetic energy, and the high strength backing plate undergoes plastic deformation, absorbing the bullet's residual energy. Ballistic tests revealed that an 8 mm thick S80B20 ceramics produced at a sintering temperature of 2120° or 2140°C, combined with a composite plate, can successfully resist.30-06 armorpiercing rounds with energy greater than 3900 J. The optimal SiC plate meeting the NIJ 0101.06 Level IV was an 8 mm thick SiC sheet backed with 9 mm of fiber board (total thickness, 17 mm; areal density, 33.217 g/m2). The 8 mm thick 80% SiC/20% B4C plate sintered at 2120°C, backed with 7 mm fiber board, had an areal density of only 29.615 kg/m2. If the depth of penetration is less than 44 mm, the fiber board thickness must be increased from 7 to 8 mm, increasing the areal density to 30.552 kg/m2. Compared with the SiC ballistic plate, the density of the composite is 2.665 kg/m2 lower. [ABSTRACT FROM AUTHOR]

The isothermal melting behaviors of ultra‐high molecular weight polyethylene (UHMWPE) with different entangled states (i.e., nascent and melt‐crystallized samples) are studied. For two kinds of UHMWPE samples, the result shows that the relative content of survived crystals (Xs) exponentially decreases with time and reaches a constant value. It is suggested that such a melting behavior is related to the observed nonlinear growth of crystals induced by the kinetically rejected entanglements accumulated at the growth front. Additionally, the exponential decay of Xs with time provides a characteristic melting time (τ) for the melting process. Compared to the melt‐crystallized UHMWPE, the τ value of nascent UHMWPE is generally longer even in a higher temperature range, which is mainly because the former has a larger entanglement density difference. Furthermore, these observations demonstrate that UHMWPEs with different entangled states have an analogous melting mechanism since they exhibit a similar melting activation energy (≈1300 kJ mol−1). [ABSTRACT FROM AUTHOR]

The goal of the study was to compare the surface characteristics of typical implant materials used in orthopedic surgery and traumatology, as these determine their successful biointegration. The morphological and chemical structure of Vortex plate anodized titanium from commercially pure (CP) Grade 2 Titanium (Ti2) is generally used in the following; non-cemented total hip replacement (THR) stem and cup Ti alloy (Ti6Al4V) with titanium plasma spray (TPS) coating; cemented THR stem Stainless steel (SS); total knee replacement (TKR) femoral component CoCrMo alloy (CoCr); cemented acetabular component from highly cross-linked ultrahigh molecular weight polyethylene (HXL); and cementless acetabular liner from ultrahigh molecular weight polyethylene (UHMWPE) (Sanatmetal, Ltd., Eger, Hungary) discs, all of which were examined. Visualization and elemental analysis were carried out by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Surface roughness was determined by atomic force microscopy (AFM) and profilometry. TPS Ti presented the highest Ra value (25 ± 2 μm), followed by CoCr (535 ± 19 nm), Ti2 (227 ± 15 nm) and SS (170 ± 11 nm). The roughness measured in the HXL and UHMWPE surfaces was in the same range, 147 ± 13 nm and 144 ± 15 nm, respectively. EDS confirmed typical elements regarding the investigated prosthesis materials. XPS results supported the EDS results and revealed a high % of Ti4+ on Ti2 and TPS surfaces. The results indicate that the surfaces of prosthesis materials have significantly different features, and a detailed characterization is needed to successfully apply them in orthopedic surgery and traumatology. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysis is the most widely used process for ethylene polymerization in industry. Active site distribution is one of the crucial issues in the heterogeneous catalysis, which strongly influences the catalytic process and the microstructure of synthesized polyethylene. In this respect, aiming at an explicit understanding of the progress, the challenge and the possible future directions in the study of heterogeneous catalysis of ethylene polymerization, the recent strategies of designing heterogeneous catalysts are reviewed from the perspective of tailoring the active site distribution, where the regulation of chain structures, including molecular weight distribution, branch distribution and entanglement state, are highlighted. The in situ and operando characterizations are also reviewed for assisting the understanding of structural information in heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

The effect of particle size and oxidation degree of new carbon microfillers, based on coal pitch (CP) and petroleum pitch (PET) cokes, on the structure as well as thermal, mechanical, and electrical properties of the composites based on ultrahigh molecular weight polyethylene (UHMWPE) was investigated. The composites studied have a segregated structure of filler particle distribution in the UHMWPE matrix. It was found that composite with smaller CP grain fraction has the highest Young's modulus and electrical conductivity compared to the other composites studied, which can be the result of a large contribution of flake-shaped particles. Additionally, conductivity of this composite turned out to be similar to composites with well-known carbon nanofillers, such as graphene, carbon black, and CNTs. Additionally, the relationship between electrical conductivity and Young's modulus values of composites studied was revealed, which indicates that electrical conductivity is very sensitive to the structure of the filler phase in the polymer matrix. In general, it was established that the properties, especially the electrical conductivity, of the composites studied strongly depends on the size, shape, and oxidative treatment of CP and PET filler particles, and that the CP coke of appropriately small particle sizes and flake shape has significant potential as a conductive filler for polymer composites. [ABSTRACT FROM AUTHOR]

There is a recognized need for developing renewable energies and in this regard, gasification process. As a result, much research is being conducted on gasification of different materials and particularly, plastic waste. Although several studies have investigated different types of models to predict gasification performance, there are few studies to predict polyethylene waste performance in gasification using multilayer perceptron (MLP) machine learning algorithms and interpreting them using multi-criteria decision-making methods. The main aims of this study are to develop MLP artificial neural networks and regression models to predict polyethylene gasification performance with high accuracy and to compare the accuracy of the models developed to determine the best one, moreover, to rank different tests using the TOPSIS method to determine the best and worst trials. One of the finding of this research is an MLP model developed and tuned according to hyperparameters with an accuracy of 99.93% with 0.190 of root mean square error, 0.003 of mean absolute error, and 0.058 of mean absolute percentage error. The research results represent a further step towards developing machine learning algorithms instead of classic regression models in polyethylene gasification. One regression model is needed for each output variable; however, this problem is solved by artificial neural networks by developing only one model. Moreover, the results showed that the using of TOPSIS and machine learning methods can be an efficient method for ranking and predicting polyethylene gasification properties. [ABSTRACT FROM AUTHOR]

The ability of the floating offshore wind turbine foundation to withstand harsh wind and wave conditions is intrinsically linked to the meticulousness employed in the design of the mooring system. Therefore, it is vital to conduct research to reveal the variations in sensitivity of new mooring materials parameters and the response characteristics of the foundation in the presence of intricate operational circumstances. A fully coupled time-domain dynamic analysis is performed via the commercial software AQWA to examine the VolturnUS-S semi-submersible foundation, specifically engineered to support the IEA 15 MW offshore reference wind turbine. The numerical simulation results indicate that synthetic fibers, specifically Aramid and high-modulus polyethylene, can replace the steel wire as mooring materials. At the same time, the mooring arrangement, length, diameter, and fairlead position influence foundation motions and mooring tensions, bringing valuable insight into the fluctuation patterns of these responses. [ABSTRACT FROM AUTHOR]

While titanium nitride (TiN) coatings are well known for their biocompatibility and excellent mechanical properties, their wear particle and debris release in orthopedic implants remains a matter of active investigation. This study addresses the efficacy of TiN coatings on CoCrMo and Ti6Al4V alloys to enhance wear resistance and reduce ion release from prosthetic implants. Three different coating variants were utilized: one variant deposited using arc evaporation (Arc) followed by post-treatment, and two variants deposited using high-power impulse magnetron sputtering (HiPIMS) with or without post-treatment. The coatings' performance was assessed through standard wear testing against ultra-high-molecular-weight polyethylene (UHMWPE) in bovine serum lubricant, and in the presence of abrasive PMMA bone cement particles in the lubricant. The results indicated that Arc and HiPIMS with post-treatment significantly reduced wear and eliminated detectable metal ion release, suggesting that these coatings could extend implant longevity and minimize adverse biological responses. Further long-term simulator and in vivo studies are recommended to validate these promising findings. [ABSTRACT FROM AUTHOR]

Conductive polymer composites are widely used for electromagnetic radiation protection. Several strategies can be employed for creating shield materials with enhanced efficiency: the use of a hybrid filler that contains nanoparticles of different types, specific structural design, and methods for decreasing the percolation threshold. We present the study of segregated polymer composites (SPCs) with ultrahigh molecular weight polyethylene (UHMWPE) matrix and hybrid fillers of NiFe-decorated graphite nanoparticles (GNPs). The microstructure, electrical percolation behavior, and electromagnetic shielding efficiency of the developed SPCs as a function of conductive filler content are determined. The combination of the advantages of the segregated structure with a synergistic effect of a hybrid filler in (GNP-NiFe)/UHMWPE allows decreasing the percolation threshold to 0.45 vol. %. The enhanced shielding efficiency of 37 dB in the frequency range of 26–37.5 GHz is achieved at the filler content of 3.4 vol. % in 1 mm thick composite samples. The dominant shielding characteristic of absorption renders hybrid composites with a segregated structure promising materials. [ABSTRACT FROM AUTHOR]

Simple Summary: Carpometacarpal and tarsometatarsal instabilities are rare diseases in dogs as compared to subluxations of the other joints of the carpus and the tarsus. Arthrodesis, skeletal external fixator use and ligament reconstruction are the most common surgical procedures for this pathology; however, high complication rates have been reported. This case report describes a novel procedure for the treatment of valgus instability of the carpometacarpal and tarsometatarsal joints using ultra-high-molecular-weight polyethylene suture (Isolock Intrauma®). The clinical and radiological findings are reported and a detailed description of the surgical technique is provided. The long-term outcomes reported in this study suggest that using a medial joint reinforcement system can be an easy, safe and effective treatment for joint instability. This case report describes a novel procedure using the Isolock Intrauma® implant system for treating medial instability of the carpometacarpal and tarsometatarsal joints, as demonstrated in in two dogs. A 9-year-old spayed female Spanish greyhound presented with a non-weight-bearing right hindlimb following a trauma. The clinical and radiological findings confirmed medial tarsometatarsal instability consistent with valgus deviation of the tarsus and the opening of the joint line on the medial aspect from the first to the third tarsometatarsal joints. A 4-year-old female Drahthaar presented with a non-weight-bearing left forelimb, swelling of the carpus and valgus instability. Radiological examination revealed a widening of the spaces between the intermedioradial carpal bone, second carpal bone and metacarpal bone II, confirming the medial carpometacarpal instability. In both cases, the Isolock system, an implant including ultra-high-molecular-weight polyethylene suture (UHMWPE), was used to reinforce the medial joint structures. Minor short-term complications were observed, such as swelling of the tarsal surgical site and hyperextension of the carpus, but these resolved spontaneously. No lameness or major complications were reported five months postoperatively. Carpometacarpal and tarsometatarsal instabilities are rare diseases in dogs as compared to subluxations of the other joints of the carpus and tarsus. There are no previous reports regarding the use of a UHMPWE implant for the treatment of these rare joint injuries, though the present case report suggests the validity and efficacy of the Isolock Intrauma® implant for restoring carpal and tarsal stability and preserving joint mobility. [ABSTRACT FROM AUTHOR]

Majority of ultrahigh molecular weight polyethylene (UHMWPE) medical devices used in total joint arthroplasty are cross‐linked using gamma radiation to improve wear resistance. Alternative methods of cross‐linking are urgently needed to replace gamma radiation due to rapid decline in its supply. Peroxide cross‐linking is a candidate method with widespread industrial applications. Oxidative stability and biocompatibility, which are critical requirements for medical device applications, can be achieved using vitamin‐E as an additive and by removing peroxide by‐products through high‐temperature melting, respectively. We investigated compression molded UHMWPE/vitamin‐E/di‐cumyl peroxide blends followed by high‐temperature melting in inert gas as a material candidate for tibial knee inserts. Wear resistance increased and mechanical properties remained largely unchanged. Oxidation induction time was higher than most of the other clinically available formulations. The material passed the local‐end point biocompatibility tests per ISO 10993. Compounds found in exhaustive extraction were of no concern with margin‐of‐safety values well above the accepted level, indicating a desirable toxicological risk profile. Statement of Clinical Significance: Peroxide cross‐linked, vitamin‐E stabilized, and high‐temperature melted UHMWPE has recently been cleared for clinical use in tibial knee inserts. With all the salient characteristics needed in a material that can provide superior long‐term performance in total joint patients, peroxide cross‐linking can replace the gamma radiation cross‐linking of UHMWPE. [ABSTRACT FROM AUTHOR]

The development of catalysts has significantly advanced the progress of polyolefin materials. In particular, group 4 (Ti, Zr, Hf) non-metallocene catalysts ligated with [N,N] bidentate ligand(s) have garnered increasing attention in the field of olefin polymerization due to their structurally stability and exceptional polymerization behaviors. Ligands containing nitrogen donors are diverse and at the core of many highly active catalysts. They mainly include amidine, guanidinato, diamine, and various N-heterocyclic ligands, which can be used to obtain a series of new polyolefin materials, such as ultrahigh molecular weight polyethylene (UHWMPE), olefin copolymers (ethylene/norbornene and ethylene/α-olefin) with high incorporations, and high isotactic or syndiotactic polypropylene after coordination with group 4 metals and activation by cocatalysts. Herein, we focus on the advancements and applications of this field over the past two decades, and introduce the catalyst precursors with [N,N] ligand(s), involving the effects of ligand structure, cocatalyst selection, and polymerization conditions on the catalytic activity and polymer properties. [ABSTRACT FROM AUTHOR]

A new fluorine-containing OOO2−-type chelating ligand and the titanium(iv) dichloride and bis-isopropoxide complexes with this ligand were synthesized. The structure of the titanium(iv) bis-isopropoxide complex was determined by single-crystal X-ray diffraction analysis. In the presence of Al/Mg activators (Et2AlCl-Bu2Mg or Et3Al2Cl3-Bu2Mg), both complexes catalyze the ethylene polymerization giving ultra-high-molecular-weight polyethylene with a molecular weight of up to 5.8 • 106 Da. Due to a low degree of polymer entanglement, these polymers can be processed by a solvent-free method to prepare high-strength high-modulus films with a Young's modulus up to 117 GPa and a tensile strength up to 2.18 GPa. [ABSTRACT FROM AUTHOR]

Human joint prostheses experience wear failure due to the complex interactions between Ultra-High-Molecular-Weight Polyethylene (UHMWPE) and Cobalt-Chromium-Molybdenum (CoCrMo). This study uses the wear classification to investigate the gradual and progressive abrasive wear mechanisms in UHMWPE. Pin-on-disc tests were conducted under simulated in vivo conditions, monitoring wear using Acoustic Emission (AE). Two Machine Learning (ML) frameworks were employed for wear classification: manual feature extraction with ML classifiers and a contrastive learning-based Convolutional Neural Network (CNN) with ML classifiers. The CNN-based feature extraction approach achieved superior classification performance (94% to 96%) compared to manual feature extraction (81% to 89%). The ML techniques enable accurate wear classification, aiding in understanding surface states and early failure detection. Real-time monitoring using AE sensors shows promise for interventions and improving prosthetic joint design. [ABSTRACT FROM AUTHOR]

Stress whitening is one of the most prominent macroscopic defects for polyethylene (PE), which greatly affects the appearance and quality of its commodity. In order to eliminate the stress whitening defects of PE, ultrahigh molecular weight polyethylene (UHMWPE) was blended with PE to fabricated PE/UHMWPE, and the enhanced intermolecular entanglement and stretchability was achieved, which greatly suppressed and impeded the occurrence of heterogeneous plastic deformation and fibrillar bundle structure during applying tensile stress, resulting in the sharply deceased of the nanoscale cavities defects for the sample. And thus, the elimination of stress whitening defects and high‐light transmittance in the visible region with excellent optical transparency performance were successfully achieved for PE/UHMWPE. Moreover, introduction of UHMWPE chains significantly improved the orientation degree and formed a dense oriented crystalline network with fine lamellae for the sample, which highly enhanced the mechanical strength of PE/UHMWPE after applying stress. This work provided a new strategy for developing stress whitening eliminating polyolefin materials with high performance, which was of great significance for sustainable development and environmental friendliness. [ABSTRACT FROM AUTHOR]

Processing of ultrahigh molecular weight polyethylene (UHMWPE) involves sintering due to its high melt strength and no flowability above melting temperature. Variations in compression molding pressure during sintering lead to chain rearrangement at the sintered interphase and the boundary, affecting foamability. UHMWPE particles are sintered using compression molding; samples are prepared at two different pressures: UHPE‐HP (80 bar) and UHPE‐LP (40 bar) at 180°C. The sintering phenomenon of UHMWPE particles is observed through an optical microscope, and their effect on foaming was observed. UHPE‐HP foams are systematically studied to obtain the foaming window. Increasing foaming pressure (80–120 bar) made UHPE‐HP foams softer (0.350–0.219 g/cm3) with varying average cell size (26.37–46.1 μm) and foam cell density (3.98 × 107–1.06 × 108 cells/cm3), and compression modulus decreased from 9 to 5.4 MPa. DMA results showed a strong dependence of stiffness on crystallinity, and foamed samples exhibit higher stiffness than their unfoamed counterpart. The storage modulus for foamed samples decreases with increase in the gas content. The UHPE‐LP foam is relatively softer, with a lower foam density (0.233 g/cm3), a higher expansion ratio, bigger average foam cells (35.13 μm), and lower foam cell density (9.33 × 107 cells/cm3). This is due to constrained crystallinity at the interphase and pre‐existing cavities, favoring the foaming. [ABSTRACT FROM AUTHOR]

Moisture damage is a prevalent failure in asphalt pavements, which is directly linked to stripping and bitumen-aggregate adhesion. Also, it can lead to other main damages. This research aims to evaluate the adhesion and moisture susceptibility of asphalt mixes containing a new polymer additive namely ultra-high-molecular-weight polyethylene (UHMWPE) with 2 and 4% bituminous weight was performed. Moreover, the tensile strength ratio (TSR), boiling water test by the image processing of coating ratio ((CR) index), and surface free energy (SFE) were conducted and compared. The results indicated that adding 4% UHMWPE to the base bitumen (B-B) increased the 27% TSR index and 31% CR index compared to the base mixtures (without additive). The best performance in the mixture of limestone (LS) and bitumen was associated with 4% UHMWPE (LS-B-UHMWPE4), in which both TSR and CR indices had the highest values. The results of SFE components indicated that the free cohesion energy in modified bitumens has increased substantially by 65% compared to B-B. Additionally, the free adhesion energy in modified bitumens with limestone and granite has demonstrated higher values. The highest increase in TSR, CR, and SFE indices was observed in the modified mixture with LS-B-UHMWPE 4. [ABSTRACT FROM AUTHOR]

For the first time, a highly crystalline porous shish-kebab structure with a high degree of crystallinity was obtained by using a combination of two methods for the formation of porous polymeric materials. A treatment procedure using supercritical carbon dioxide (scCO2) was carried out for oriented ultrahigh molecular weight polyethylene (UHMWPE) films, which provided special conditions for the crystallization of dissolved UHMWPE macromolecules on the surface of oriented UHMWPE crystals. The prepared porous materials were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The particularity of the obtained porous shish-kebab is the absence of the amorphous phase between lamellar crystals (kebabs). The obtained pores had an oval shape, and they were oriented in the orientation direction of the UHMWPE macromolecules. The pore size ranged from 0.05 µm to 4 µm. Controlling the conditions for the crystallization of the UHMWPE macromolecules using supercritical CO2 gives the possibility to control the size of both lamellar disks and pores formed. [ABSTRACT FROM AUTHOR]

For the first time, a highly crystalline porous shish-kebab structure with a high degree of crystallinity was obtained by using a combination of two methods for the formation of porous polymeric materials. A treatment procedure using supercritical carbon dioxide (scCO2) was carried out for oriented ultrahigh molecular weight polyethylene (UHMWPE) films, which provided special conditions for the crystallization of dissolved UHMWPE macromolecules on the surface of oriented UHMWPE crystals. The prepared porous materials were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The particularity of the obtained porous shish-kebab is the absence of the amorphous phase between lamellar crystals (kebabs). The obtained pores had an oval shape, and they were oriented in the orientation direction of the UHMWPE macromolecules. The pore size ranged from 0.05 µm to 4 µm. Controlling the conditions for the crystallization of the UHMWPE macromolecules using supercritical CO2 gives the possibility to control the size of both lamellar disks and pores formed. [ABSTRACT FROM AUTHOR]

High-performance polyethylene fibers, renowned for their superior attributes encompassing a high strength, modulus, and lightness, are conventionally manufactured through the gel spinning method. However, this method is encumbered by several drawbacks, including the requisite application of a separate process to eliminate solvents from the fibers and the utilization of chemicals deleterious to both the environment and human health. Alternatively, the adoption of the melt spinning method presents a cleaner and environmentally friendly approach to attain high-performance fibers. In the present investigation, high-density polyethylene (HDPE) fibers were produced employing the melt spinning method. After the spinning process, strategic orientation procedures were implemented to enhance the crystallinity of the spun fibers. As a concluding step, seeking to elevate the overall performance of the oriented spun HDPE fibers, a cross-linking treatment was applied via UV irradiation. Notably, this study pioneers the incorporation of polyhedral oligomeric silsesquioxane (POSS) hybrid nanoparticles into HDPE during melt spinning, presenting a novel advancement aimed at further enhancing the mechanical properties of oriented HDPE fibers during UV irradiation. For this purpose, two distinct types of POSS, namely octavinyl POSS (OVPOSS) and methacryl POSS (MACPOSS), both having unsaturated double bonds capable of participating in the network structure of oriented HDPE spun during UV cross-linking, were used. The thermal, morphological, and mechanical properties, as well as the crystal structure of samples with and without POSS molecules, were investigated. The mechanical properties of the fibers exhibited higher values in the presence of OVPOSS. The incorporation of OVPOSS and MACPOSS resulted in a noteworthy improvement in the material's tensile strength, exhibiting a marked increase of 12.5 and 70.8%, respectively. This improvement can be attributed to the more homogeneous dispersion of OVPOSS in HDPE, actively participating in the three-dimensional network structure. After orientation and UV irradiation, the tensile strength of HDPE fibers incorporating OVPOSS increased to 293 MPa, accompanied by a concurrent increase in the modulus to 2.8 GPa. The addition of POSS nanoparticles thus yielded a substantial improvement in the overall performance of HDPE fibers. [ABSTRACT FROM AUTHOR]

a method for calculating the size distribution of nanocrystalline elements of the polymer structure is proposed. The longitudinal size distribution (thickness) of ultrahigh molecular weight polyethylene lamellae was calculated from calorimetric data. The results of calculating the maximum values of the distribution are consistent with the known data obtained by other methods. [ABSTRACT FROM AUTHOR]

To understand the hybrid fiber enhanced impact‐resistance performance of composite laminates. In particular, the effects of different parameters, such as hybrid fiber ratios and plying modes, were investigated. The effects of UHMWPE short fibers (UHMWPESFs) fiber content and ply angle changes on the impact resistance of Carbon fiber/ultra‐high molecular weight polyethylene short fiber hybrid composite (CUFHRP) laminates were investigated in this article. The impact resistance of the CUFHRP laminate was tested by the drop weight test and residual strength test after impact. The results indicated that the peak load and absorption energy of the specimen with a fiber content of 15 g/m2 were the highest, reaching 6.543 kN and 16.51 J, respectively. Specimens with different ply modes of [0/−45/45/90]2s showed the most obvious effect on the maximum load. Its maximum load was 28.93% higher than that of the original sample. The critical damage threshold load of composite laminates is improved, and the impact resistance is strengthened. Highlights: Study to improve the impact resistance of the composite on the basis of the hybrid structure.Report the optimal parameters of the effects on the impact resistance of the composite, such as: hybrid fiber ratios and plying modes.Reveal the fundamental failure mode of hybrid structure composite laminates under low‐velocity impact. [ABSTRACT FROM AUTHOR]